Tiny tots will miss out on playtime after the premises where they meet were badly damaged by fire.
Kirkliston playgroup will be shut for at least a month after the sports pavilion in Alison Park was deliberately targeted.
No one was harmed but there was significant fire damage to the roof and walls after Monday’s incident.
Police believe the blaze was started deliberately and an investigation is under way.
The playgroup, which has 24 members and more due to start this month, will not be open and will be without funding this month.
Children’s toys melted in the fire while the inside of the building will need to be refurbished because of smoke damage.
Helen Hogg, chairperson of the playgroup committee, said: “I’m massively disappointed that anybody could be involved.
“I’m a youth worker so I wouldn’t like to cast aspersions on this being youths with nothing better to do, but whoever has done it clearly hasn’t thought about the consequences.
“This playgroup has been running for 30 years and it has had a huge impact on the community.
“That said, I’m encouraged by the response from the community. There has been a massive outpouring, people have been contacting us asking how they can help and what they can do to get us back up and running.
“We won’t be able to start in January but we are aiming to open on February 6.”
PC Neil Donnelly said: “We believe this fire to be suspicious and we are eager to trace the person responsible as soon as possible.
“I would ask that anyone who was in the Allison Park area of Kirkliston around 8pm on January 2, and saw anything suspicious, get in touch as soon as possible.”
l Call Police Scotland on 101 or anonymously through Crimestoppers on 0800 555 111.